The present invention relates generally to transducers or pickups for musical instruments and, more particularly, to an improved transducer that is flexible, shielded, light weight, accurate, and repositionable, and that may conveniently be used with a variety of stringed and percussive instruments.
Existing products for recording and amplifying sounds produced by musical instruments generally fall into the categories of microphones, magnetic pickups, contact pickups, and in-the-saddle pickups.
Microphones are generally expensive and have inherent frequency response limitations due to the size, shape, and mass of the diaphragm element that produces the electrical signal. Microphones require air pressure to actuate a diaphragm, which in turn produces an electrical signal. Thus, the electrical signal is not produced instantaneously, but is instead slightly delayed due to the compressive nature of air. Furthermore, microphones have a resonant frequency in the range of 8 kHz-14 kHz, which colors the sound produced with an un-natural boost in output in that frequency range.
Magnetic pickups require the use of ferrous metal strings on the instrument to which they are attached and are placed in positions along the length of those strings in order to produce electrical images of the strings at those harmonic points. The total harmonic content of the signal is limited to the position of the pickup. Magnetic pickups exert a very strong magnetic force on the instrument strings, thereby altering their natural movements and reducing sustain, harmonic balance, and string energy considerably. Magnetic pickups are not practical for use with instruments having more than twelve strings, such as pianos, since the length of the coil windings and the weight of the magnets would substantially reduce the performance of those types of instruments.
Contact pickups are usually rigid ceramic/crystalline piezo materials that are typically deposited onto rigid metal substrates. Most of these pickups are further limited by being encapsulated into plastic cases using epoxy resins. The resulting rigidity and mass diminishes the accurate performance of the pickup. The mass creates audible resonant frequencies, and also alters the natural sound of the instrument. Ceramic piezo materials have a mass that creates a non-musical self resonance between 6 and 16 kHz, and they exhibit a very non-linear frequency response that resembles white noise.
In-the-saddle pickups place a compressible material precisely at the point where the string energy enters the body of the instrument through the bridge, thus noticeably altering the natural tone, sustain, and dynamic response. Saddle pickups respond primarily to the strings of the instrument, rather than to the instrument itself. String balance is difficult to achieve with saddle pickups, resulting in one or more of the strings being too loud or too quiet, relative to the others.
Exemplary of prior art transducers or pickups are those described in U.S. Pat. No. 4,727,634 to Fishman, U.S. Pat. No. 5,123,325 to Turner, U.S. Pat. No. 5,204,487 to Turner, U.S. Pat. No. 5,319,153 to Fishman, U.S. Pat. No. 5,670,733 to Fishman, U.S. Pat. No. 5,817,966 to Fishman, U.S. Pat. No. 5,866,835 to Baggs, U.S. Pat. No. 5,900,572 to Aaroe, and U.S. Pat. No. 6,023,019 to Baggs.